1. Field of the Invention:
The present invention relates to a multimode service radio communication method and apparatus for providing broadcasting and communication services between a base station and individuals or vehicle occupants using a specific common radio frequency band in radio systems including mobile (pocket) telephone communication systems and broadcasting systems, intelligent transport systems, etc.
2. Description of Prior Art:
Mobile telephone communication services and broadcasting services have been provided using specific frequency bands corresponding to the kinds of services and using users"" terminals provided with radio-frequency units and antennas corresponding to the respective specific frequency bands. Individuals or vehicle occupants on the users"" side have individual transceivers as many as the services, receive broadcasting services and utilize mobile communication.
A prior art radio system scheme for providing services to vehicle occupants is shown in FIG. 5. Its principal services include personal digital cellular. (PDC) communication operating in the 800 MHz or 1.5 GHz frequency band, a vehicle information and communication system (VICS) using a beacon operating in the 2.5 GHz frequency band, frequency modulation (FM) broadcasting operating in the 76 to 90 MHz frequency band, television (TV) broadcasting operating in the 90 to 770 MHz frequency band, and digital broadcasting operating in the 12 GHz frequency band.
In the broadcasting and mobile communication services utilizing the conventional technologies, however, since the frequency bands to be used differ from one another depending on the kind of service, multiple mobile communication terminals and broadcasting receiver terminals are required. A vehicle has to be provided with a separate radio-frequency unit and antenna corresponding to each of the various frequency bands. With future scale-enlargement and introduction of various new services likely, the limited internal space of a vehicle is apt to be insufficient for installation of the required equipment. In addition, the inside of a tunnel, a place surrounded by a soundproof barrier, a valley between tall buildings, etc. still constitute zones not reached by radio waves. Moreover, users have to carry around a plurality of terminals and use the terminals properly in accordance with the service to be received.
One object of the present invention is to provide a multimode service radio communication method and apparatus using a single terminal to receive multimode services of a radio information and communication providing system including a digital broadcasting service, a PDC mobile communication system, and a personal handy-phone system (PHS).
Another object of the present invention is to provide a multimode service radio communication method and apparatus suitable for a vehicle because the apparatus is made simple and compact by integrating a plurality of radio-frequency units and a plurality of antennas into a single radio-frequency unit and a single antenna each usable in common.
To attain these objects, according to the present invention there is provided a method for providing a hand-held or vehicle-mounted terminal with radio communication and radio broadcasting information of a radio information and communication providing system including mobile communication systems and intelligent transport systems, comprising the steps of integration-converting individual radio or intermediate frequencies modulated for mobile telephones and broadcasts into radio signals in the specific frequency band so that the modulated frequencies are included in a specific frequency band; causing an antenna to transmitting the radio signals to a shared antenna; and selectively linking a specific frequency in the specific frequency band to the hand-held or vehicle-mounted terminal, thereby receiving a communication or broadcasting service of the specific frequency.
The radio signals received by the shared antenna are converted into the individual radio or intermediate frequencies. The converted individual frequencies are allocated to the hand-held or vehicle-mounted terminal.
The radio signals in the specific frequency band are converted into optical signals. The optical signals are transmitted to the antenna via optical fibers and converted into radio signals. The converted radio signals are transmitted from the antenna to the shared antenna.
The present invention also provides a multimode service radio communication apparatus that provides a hand-held or vehicle-mounted terminal with radio communication and radio broadcasting information of a radio information and communication providing system including mobile communication systems and intelligent transport systems, which comprises a frequency division multiplexer that integration-converts individual radio or intermediate frequencies modulated for mobile telephones and broadcasts so that the modulated frequencies are included in a specific frequency band, and produces radio signals in the specific frequency band; supply means for supplying the radio signals; an antenna for receiving and transmitting the supplied radio signals; a shared antenna for receiving the transmitted radio signals; and terminals to which specific frequencies in the specific frequency band are selectively linked; whereby communication or broadcasting services are received using the terminals.
The apparatus is provided with means for converting the radio signals received by the shared antenna into the individual radio or intermediate frequencies and allocating the individual frequencies to the hand-held or vehicle-mounted terminals.
The terminals constitute a multimode terminal. The supply means comprises means for converting the radio signals into optical signals, optical fibers for transmitting the optical signals, and means for receiving the transmitted optical signals, converting the received optical signals into radio signals and transmitting the converted radio signals to the antenna. The shared antenna is mounted on a vehicle.
In the present invention, as described above, since individual radio or intermediate frequencies modulated for mobile telephones and broadcasts are integration-converted so that the modulated frequencies are included in a specific frequency band, a single terminal to which specific frequencies in the specific frequency band are selectively linked is used to receive a plurality of mobile communication and broadcasting services.
Futhermore, since each of a single antenna and a single radio-frequency unit can be used in common, the apparatus can be made compact to enable the apparatus to be advantageously mounted on a vehicle having a small internal space.
The above and other objects, features and advantages of the present invention will become apparent from the description made with reference to the accompanying drawings.